The consensus for today's GDP reading among forecasters was for a big increase to 4.1% or 4.2% depending on who does your data aggregation.  Either way, that's a big jump from the previous reading of 2.0% (now revised to 2.2%).  When key data is seen rising that much, economists have a tendency to undershoot the jump.  Traders know it.  As such, they get in position for an even bigger move than the forecast suggests.

When GDP merely came in "as-expected," bonds breathed a sigh of relief with a modest rally.  It was more of a token, really, as yields never threatened yesterday's lows.  Stocks confirmed the anticipation with by selling-off at the open (i.e. stocks were also expecting a bigger number,  and thus gave up ground when it was "only" 4.1%).

Next week is a minefield of data and events for bonds.  While 10yr yields were able to find a ceiling right in line with early June highs just under 3%, anything is possible if next week's data is cohesive.  In other words, if multiple reports suggest the economy strengthened in July, it wouldn't be a surprise to see 10's move up and over 3%.  Conversely, if the data cools. that early June ceiling could be reinforcedb.